In a new development update posted to the official Civilization III web site, Jeff Morris of Firaxis explains how they plan to implement multiplayer gameplay in the upcoming Play the World expansion pack. The most startling change in the works is that, while the Civilization series has dominated the world of turn-based games since its inception, the team plans to let players battle against eachother in a "turnless" gameplay mode.

While the add-on will still ship with the standard turn-based play many gamers love, Morris describes how the nature of long, multi-session games didn't always work well in the modern internet gaming environment. Thus they came to the idea of speeding up the process with new "meta-games" for those looking for a quick Civilization III fix, as well as the Turnless mode. Here's more of an description of how it will work from Morris:

For the first time in a Civilization game, through the use of a "Turnless" game system, we can offer a much faster paced gaming mode. In Turnless, each unit and city has its own turn clock. These clocks progress independently from each other, meaning that a unit that has just moved, can't move again until its clock has reset. It is impossible for a single player to hold up the progress of the game (which happens sometimes in turn based games when played online). With Turnless, they're really only forfeiting their own moves. In addition we offer speed controls to the player, which determine how long each of these turn clocks take to reset. When combined with the dynamic scaling we apply, based on the number of units and cities each player possesses, the game allows players to configure the settings and determine their own pacing.